attached are cross overs of basic polk sda. sda 2a
and some information about the speakers. i know it's polk and all that. but i am mostly interested in cross talk cancellation in these cross overs.
the speakers consist of two 6.5" midbasses(8ohm each) and one 1" tweeter.
inner midbass and tweeter create a regular signal of a regular 2 way speaker. i could trace this in the cross over diagram
the outer midbass driver(dimentional driver) plays out of phase signal of the opposite speaker. speakers are connected with a 2 wire cable to exchange signals from left to right speakers.
from what i've seen online this cross talk cancelation is only utilized in 150hz-2000hz region.
so there is no cross talk cancelation above 2000hz or under 150hz
below 150hz that dimentional driver helps the stereo driver with bass output. so it does not do cross talk cancelation below 150hz
i am having difficult time finding out which part of the cross over diagram turns the dimentional driver into a bass driver under 150hz
i would like to change the cross overs into regular 2 way system with cross cancelation. it looks like original set up is some sort of 2.5 way system.
so id like the dimentional driver to always do cross cancelation. not only 150hz-2000hz. but in all frequencies under 2000hz
thanks in advance. and if any other parameters are needed can provide. didn't want to make this thread two burdensome with values and graphs.
have specs for drivers and tweeter.
and some information about the speakers. i know it's polk and all that. but i am mostly interested in cross talk cancellation in these cross overs.
the speakers consist of two 6.5" midbasses(8ohm each) and one 1" tweeter.
inner midbass and tweeter create a regular signal of a regular 2 way speaker. i could trace this in the cross over diagram
the outer midbass driver(dimentional driver) plays out of phase signal of the opposite speaker. speakers are connected with a 2 wire cable to exchange signals from left to right speakers.
from what i've seen online this cross talk cancelation is only utilized in 150hz-2000hz region.
so there is no cross talk cancelation above 2000hz or under 150hz
below 150hz that dimentional driver helps the stereo driver with bass output. so it does not do cross talk cancelation below 150hz
i am having difficult time finding out which part of the cross over diagram turns the dimentional driver into a bass driver under 150hz
i would like to change the cross overs into regular 2 way system with cross cancelation. it looks like original set up is some sort of 2.5 way system.
so id like the dimentional driver to always do cross cancelation. not only 150hz-2000hz. but in all frequencies under 2000hz
thanks in advance. and if any other parameters are needed can provide. didn't want to make this thread two burdensome with values and graphs.
have specs for drivers and tweeter.
Attachments
What the Heck is this speaker supposed to do? 
Apparently it widens the stereo image:
http://www.hifi-classic.net/review/polk-audio-sda-2a-181.html
I am mulling this Hare-brained idea over. I have some recall that Bud Fried invented this circuit.
Anyway, I have redrawn it into some sort of directly viewable form, because PDFs are not open-source.
Looks like 6" bass plus 1" tweeter at heart, with low crossover around 1.5kHz.
Next step is to redraw it better, and simulate it I suppose. Those who used to own Boom-boxes will recall the (electronic) Stereo-Wide button.
Made Mono sound a bit like Stereo. Made Stereo sound more vivid. Where I've got to so far.
Apparently it widens the stereo image:
http://www.hifi-classic.net/review/polk-audio-sda-2a-181.html
I am mulling this Hare-brained idea over. I have some recall that Bud Fried invented this circuit.
Anyway, I have redrawn it into some sort of directly viewable form, because PDFs are not open-source.
Looks like 6" bass plus 1" tweeter at heart, with low crossover around 1.5kHz.
Next step is to redraw it better, and simulate it I suppose. Those who used to own Boom-boxes will recall the (electronic) Stereo-Wide button.
Made Mono sound a bit like Stereo. Made Stereo sound more vivid. Where I've got to so far.
Attachments
the interconnect cable "A B" reversed part of the diagram is a two wire cable that connects the speakers . this wire facilitates the stereo signal from left speaker is sent to the right speakers dimensional driver to be played out of phase and be canceled.
and vice versa: stereo signal from right speaker sent to left speakers dimensional driver to be played out of phase.
the 750pF capacitor is just to help the 12uF capacitor. i've heard old capacitors werent fast enough.
the safety guard is often removed. it's to protect tweeter from blowing
and vice versa: stereo signal from right speaker sent to left speakers dimensional driver to be played out of phase.
the 750pF capacitor is just to help the 12uF capacitor. i've heard old capacitors werent fast enough.
the safety guard is often removed. it's to protect tweeter from blowing
dont mean to complicate things... but this cross over was the most updated and improved. it's a cross over of sda-2b. its supposed to be the same speaker as sda-2a but with easer load on the amplifier.
differences are as follows
sda 2b were 6ohm.
used mw6503 or mw6510 8ohm stereo driver(inner driver)
used mw6511 4ohm dimentional driver(outer driver)
interconnect cable communicated out of phase signal between 2 speakers using only one of the wires. (labeled as IC on diagram)
so the "-" or "white" labeled wire is common ground. the grounds are connected together
the "blue" wire on diagram carries the out of phase signal between speakers.
again..not sure how can one wire send out of phase signal both ways : from left to right and from right to left
sda-2a were 4ohm
used mw6510 8ohm driver as both stereo and dimentional driver
there is a costly 260uF film capacitor in this cross over. shown as 2 130uF in parallel
interconnect signal consisted of 2 wire and each wire carried a signal. if i understand it correnctly the polarities of this interconnect wire are reversed when speakers are connected
maybe this diagram will be easier to desipher. i hope
edit: the diagram says sda-crs+ but its exactly the same cross over used in sda-2b
differences are as follows
sda 2b were 6ohm.
used mw6503 or mw6510 8ohm stereo driver(inner driver)
used mw6511 4ohm dimentional driver(outer driver)
interconnect cable communicated out of phase signal between 2 speakers using only one of the wires. (labeled as IC on diagram)
so the "-" or "white" labeled wire is common ground. the grounds are connected together
the "blue" wire on diagram carries the out of phase signal between speakers.
again..not sure how can one wire send out of phase signal both ways : from left to right and from right to left
sda-2a were 4ohm
used mw6510 8ohm driver as both stereo and dimentional driver
there is a costly 260uF film capacitor in this cross over. shown as 2 130uF in parallel
interconnect signal consisted of 2 wire and each wire carried a signal. if i understand it correnctly the polarities of this interconnect wire are reversed when speakers are connected
maybe this diagram will be easier to desipher. i hope
edit: the diagram says sda-crs+ but its exactly the same cross over used in sda-2b
Last edited: